EVgo has a history of changing chargers to suit the mix of usage. Very early on in the CCS rollout, they installed a CCS charger at the Nob Hill Foods site in Mountain View. This is only about 1/4 mile from BMW Mountain View. The site was initially a Nissan CHAdeMO and an ABB CCS-Only charger. After a little while, they changed the ABB charger for a dual CCS & CHAdeMO charger. About a year later, they changed out the Nissan CHAdeMO for another ABB dual CCS & CHAdeMO charger. Replacing chargers is not an involved process. It's just a maintenance operation, so no permits are needed or anything.
There are more Leafs on the road than all the CCS cars combined, so having more total CHAdeMO plugs does make some sense. However, the problem arises when Leaf owners arrive to an empty site and plug in to the dual charger. Then an e-Golf or an i3 arrives and they can't use the available charger. If I were to guess, I would think that EVgo is not buying any new Nissan chargers, but are re-deploying the old ones to new sites when the busy sites are upgraded to two dual standard units.